drivers/watchdog/via_wdt.c

1 // SPDX-License-Identifier: GPL-2.0-only
3  * VIA Chipset Watchdog Driver
10  * Caveat: PnP must be enabled in BIOS to allow full access to watchdog
11  * control registers. If not, the watchdog must be configured in BIOS manually.
22 #include <linux/watchdog.h>
26 #define VIA_WDT_CONF		0xec	/* watchdog enable state */
29 #define VIA_WDT_CONF_ENABLE	0x01	/* 1: enable watchdog */
30 #define VIA_WDT_CONF_MMIO	0x02	/* 1: enable watchdog MMIO */
33  * The MMIO region contains the watchdog control register and the
42 #define VIA_WDT_FIRED		0x02	/* 1: restarted by expired watchdog */
58 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, between 1 and 1023 "
63 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
72 					/* The timer that pings the watchdog */
83  * Timer tick: the timer will make sure that the watchdog timer hardware
85  *  1) the watchdog timer has been started and /dev/watchdog is open
89  *  2) the watchdog timer has been stopped by userspace.
104 	next_heartbeat = jiffies + wdd->timeout * HZ;  in wdt_ping()
112 	writel(wdd->timeout, wdt_mem + VIA_WDT_COUNT);  in wdt_start()
131 	wdd->timeout = new_timeout;  in wdt_set_timeout()
136 	.identity =	"VIA watchdog",
162 	int ret = -ENODEV;  in wdt_probe()
165 		dev_err(&pdev->dev, "cannot enable PCI device\n");  in wdt_probe()
166 		return -ENODEV;  in wdt_probe()
170 	 * Allocate a MMIO region which contains watchdog control register  in wdt_probe()
171 	 * and counter, then configure the watchdog to use this region.  in wdt_probe()
173 	 * If not, the watchdog must be configured in BIOS manually.  in wdt_probe()
177 		dev_err(&pdev->dev, "MMIO allocation failed\n");  in wdt_probe()
188 		dev_info(&pdev->dev, "VIA Chipset watchdog MMIO: %x\n", mmio);  in wdt_probe()
190 		dev_err(&pdev->dev, "MMIO setting failed. Check BIOS.\n");  in wdt_probe()
195 		dev_err(&pdev->dev, "MMIO region busy\n");  in wdt_probe()
201 		dev_err(&pdev->dev, "cannot remap VIA wdt MMIO registers\n");  in wdt_probe()
209 	wdt_dev.parent = &pdev->dev;  in wdt_probe()
218 	/* start triggering, in case of watchdog already enabled by BIOS */  in wdt_probe()
260 MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset");